A requirement exists for large commercial aircraft known as "widebodies" (such as the Boeing 767) to prevent collapse of the cabin floor during a rapid decompression situation. This is accomplished by providing a path for the rapid movement of air between aircraft cabin and the cargo compartment located below the cabin floor in the event of a rupture in the aircraft shell. In addition, there exists a requirement to provide a return air path within the environmental control system for conditioned air circulated within the aircraft cabin. To meet these requirements air grilles are installed in the passenger cabin which regulate the amount of return air flow from the cabin to the aircraft environmental control system. More specifically, the air grilles are adjusted to allow a precise amount of return airflow depending upon their location in the aircraft cabin. For example, some conventional grilles include louvers which are normally partially closed to regulate return airflow to the environmental control system but which are automatically deployed to a full open position by spring biasing during sudden decompression.
These conventional grilles are usually located in the cabin sidewall near the floor between the lower edge of each sidewall panel and the top of the floor. The amount of air flow allowed through the grilles is a function of their distance from the environmental control system recirculating air fan. In addition to providing a means of regulating airflow, the grilles must protect insulation as well as aircraft systems located behind the sidewall from damage due to cleaning equipment, under-seat passenger luggage and other passenger abuse. Furthermore, these grilles are required to block line-of-site noise transmission into the cabin as well as to function as decorative screens.
A problem with some conventional grilles are their complexity, weight, and cost. In addition, they can be difficult to repair when damaged as a result of passenger or cleaning personnel abuse.
A number of conventional air vent grilles have been disclosed. For example, U.S. Pat. No. 3,854,567 by Roach discloses an aircraft decompression panel which has a number of vertically spaced hinged louvers of airfoil design and which are caused to move to an open position during the presence of a sudden pressure differential. Furthermore, U.S. Pat. No. 4,432,514 by Brandon, and assigned to the assignee of the present invention, discloses a decompression panel having a number of openings for relieving a pressure differential between an aircraft cabin and a cargo compartment such that a valve is spring biased to cover the openings until a sudden pressure differential is present.